With reference to the strategic bombing campaign by the USAAF and RAF; One of the most critical targets was the rail transportation system of Western Europe. It was realized by Allied planners that the rail and road system provided Germany the means to react with great speed to any Allied military initiative in France or the Low Countries. Before a Cross Channel invasion could be made, two things had to happen. (1) The German Army had to be cut down to size with casualties on the Eastern Front, and (2) the transportation/communication system of Western Europe had to be severely damaged. By 1944 Germany was fighting on interior lines and could shift even it's limited resources quickly, sometimes achieving local numerical superiority in spite of it's overall numerical inferiority. The bombing campaign against the French rail system caused considerable civilian casualties because the rail lines, with marshaling and switching yards ran right through French towns. I think it's true that post - war analysis showed that the strategic bombing campaign was not as decisive as it's supporters claimed, but I maintain that it was an important contribution to final victory. Also, from 1941-1944, it was one of the only ways that the British and Americans could show the Russians that they were doing their part.